Comparison of the Complete Chloroplast Genomes of Astilbe: Two Korean Endemic Plant Species

Abstract

Background: Astilbe, consisting of about 18 species, is distributed throughout East Asia and Northeastern America, and most Astilbe species are widely cultivated as ornamental plants. A total of four species of Astilbe have been confirmed to be distributed throughout Korea, two of which are endemic to Korea. Methods: In this study, we sequenced and assembled the complete chloroplast genomes of two endemic Korean plants using Illumina sequencing technology, identified simple sequence repeats (SSRs) and repetitive sequences, and compared them with three previously reported chloroplast genomes. Results: The chloroplast genomes of the two species were 156,968 and 57,142 bp in length and had a four-part circular structure. They consisted of a large single-copy region of 87,223 and 87,272 bp and a small single-copy region of 18,167 and 18,138 bp, separated by a pair of inverted repeats (IRa and IRb, 25,789 and 25,866 bp). The genomes contained 130 genes, 49 SSRs, and 49 long repetitive sequences. Comparative analysis with the chloroplast genomes of five Astilbe species indicated that A. uljinensis was closely related to A. chinensis and A. taquetii to A. koreana. Conclusions: This study provides valuable references for the identification of two endemic Korean Astilbe species and contributes to a deeper understanding of the phylogeny and evolution of the genus Astilbe.